The present invention relates to a three-dimensional image processor and a three-dimensional image processing method, and more specifically, it relates to a three-dimensional image processor and a three-dimensional image processing method which are capable of switching, for display, between portrait and landscape orientations of a display image, and also capable of 2D/3D conversion.
In recent years, three-dimensional image technology has been attracting attention, which displays a pair of right and left video data with binocular parallax on a liquid crystal panel as video data for the right eye and video data for the left eye to provide a person viewing the video with a perception as if an object exists in three dimensions. A variety of techniques has been disclosed to realize such a three-dimensional video display. For example, there may be mentioned polarization filtering (passive type) such as μpol or Xpol (registered trademark), or electronic shuttering (active type).
As methods of capturing video signals to perform three-dimensional video display, there may be one that uses two cameras to perform image capturing, or one that performs 2D/3D conversion converting two-dimensional video signals into three-dimensional video signals as illustrated in Patent Literature 1 (Japanese Patent Application Laid-Open Publication No. 2001-298753). Particularly, since the method using 2D/3D conversion allows three-dimensional display of legacy video assets, it has been attracting attention in recent years and many studies are conducted.
On the other hand, among portable display devices, a display device becomes widespread that incorporates an aspect conversion technique which, as disclosed in Patent Literature 2 (Japanese Patent Application Laid-Open Publication No. 2010-107665), determines whether the display device is being viewed in a portrait or landscape orientation using a gravity sensor or the like, and changes the aspect of the display screen accordingly to switch between portrait and landscape orientations.
Here, a configuration is considered which realizes 2D/3D conversion in a display device capable of portrait and landscape viewing, using the technique of Patent Literatures 1 and 2.
When 2D/3D conversion is performed first and then aspect conversion is performed, a basic image 1 is converted into a 2D/3D converted image 2 as illustrated in FIG. 1, then converted into an aspect converted image 3, and becomes a completed image 4. With the method which performs 2D/3D conversion first, output signals are provided in a form in which a right-eye signal and a left-eye signal are shifted rightward and leftward. For example, a method is considered in which the right-eye signal and the left-eye signal are output for one frame, and respective signals are subjected to aspect conversion via a frame memory and output as output signals. However, the method has a problem that the required capacity of the frame memory used for aspect conversion doubles because the frame memory keeps the right-eye signal and the left-eye signal after 2D/3D conversion for each frame.
A method is conceivable which outputs the right-eye signal and the left-eye signal collectively in one frame, and performs aspect conversion via the frame memory to obtain an output signal. With this method, however, although the required capacity of the frame memory does not increase because the signal after 2D/3D conversion has a right-eye signal and a left-eye signal equivalent to one frame, the resolution of the right-eye signal and the left-eye signal falls, which leads to a problem of decreased precision of scaling performed at the time of aspect conversion.
When aspect conversion is performed first and then 2D/3D conversion is performed, the basic image 1 illustrated in FIG. 1 is converted into an aspect converted image 5, then converted into a 2D/3D converted image 6, and becomes a completed image 7. Since the method which performs aspect conversion first shifts the right-eye signal and the left-eye signal upward and downward, it is necessary to change the shift direction of 2D/3D conversion. For example, a method is conceivable in which an input signal is subjected to aspect conversion via the frame memory, and 2D/3D conversion thereafter, to be converted into an output signal. However, since the method performs 2D/3D conversion after aspect conversion, the shift direction of the right-eye signal and the left-eye signal of the output signal varies depending on whether the display unit is providing a portrait or landscape view. There arises a problem that it is necessary to prepare the line memory corresponding to the maximum shift.
Therefore, in view of the aforementioned problem, the present invention is directed to providing a three-dimensional image processor and a three-dimensional image processing method which realize 2D/3D conversion and aspect conversion with a smaller memory capacity to be used and without reducing scaling precision.